<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		
		<script>
			
			// 常量
			console.log(123);
			console.log('你好');
			console.log(true);
			
			// 变量
			var a = 123;
			console.log(a);
			a = 321;
			console.log(a);
			
			// var可以省略不写
			// var name = '张三';
			name = '张三';
			console.log(name);
			
		</script>
		
	</body>
</html>
